Police officers escort ex-chess champion and opposition leader Garry Kasparov (right) after he was detained at a protest during the Pussy Riot trial outside a court building in Moscow on August 17. Kasparov was set Monday to face police questioning after he was accused of biting a policeman. (AFP Photo/Natalia Kolesnikova)

Former chess king turned Kremlin critic Garry Kasparov faced the threat of prison Monday after being questioned over claims that he bit a policeman at the sentencing of the Pussy Riot punk rockers.

The bizarre but serious charge could put the 49-year-old behind bars for five years and deliver even graver harm to Moscow’s deteriorating relations with the West in President Vladimir Putin’s third term.

Kasparov has been a seminal figure of the opposition who has used his global fame to publish articles in the Western press detailing the difficulties human rights encountered during Putin’s previous 12 years in power.

His impact on home politics has been limited almost entirely to failed efforts to merge the various forces of Russia’s protest movement into a cohesive unit that could meaningfully take on Putin at the polls.

But he remains a constant presence at Moscow protests and was one of dozens detained in confrontations that broke out during Friday’s sentencing to two years in prison for the three feminist protest band members.

Kasparov had defended their “punk prayer” stunt performance as “political speech that should be unconditionally protected” — a view unanimously shared by Western powers but not the Kremlin or Russia’s powerful Orthodox Church.

No charges against Kasparov have yet been filed and he only appeared Monday at a Moscow district police station to give initial testimony.

The Moscow police department said it had handed over the evidence to the federal Investigative Committee that leads almost all high-profile cases against Russian opposition members.

But the charges — if pursued — could deal one of the biggest blows yet to Russia’s ties with the West that are already strained from opposing views of the Syria conflict and what is believed to be Putin’s firm decision to allow no more dissent.

Kasparov dismissed the biting allegations with characteristically bitter irony on his Twitter account.

“I am sorry if the policeman who was beating me on the head had hurt his hand,” the man widely regarded as history’s greatest chess player tweeted.

He also promised to file slander charges on Tuesday against the officer who was allegedly bitten as well as a second suit claiming illegal detention.

The world’s highest-rated chess player for nearly two decades was pulled into a waiting police van while talking to a group of reporters.

The biting claims appear to revolve around evidence volunteered by a man who heads Officers of Russia — a fringe nationalist group that on its own website sets out its mission as “providing support to the law enforcement authorities”.

Officers of Russia leader Anton Tsvetkov said he had been asked by bailiffs to keep an eye on who was breaking order at Friday’s explosive Pussy Riot verdict reading and report any incidents to the police.

“I did not personally see the bite,” Tsvetkov admitted to AFP in a telephone interview.

“But one of my assistants was told by a reporter that Kasparov had bit a policeman. She went out to investigate and eventually found the bitten policeman,” he added.

“The bite was on the hand.”

The story has gained broad attention in part because it has been played up by Kasparov himself.

He gave a host of interviews to both US and Russian media over the weekend citing the allegations as evidence that human rights under Putin were approaching a terminal state.

Yet there would appear to be little to gain for the Kremlin from jailing a figure of international stature with national approval ratings that have rarely been higher than a few percent.

An assault on a police officer conviction can result in fine of 200,000 rubles ($6,200) or up to five years in jail.